Conventionally, pneumatic rubber tires are produced by molding and curing a green, or uncured, tire in a molding press in which the green tire is pressed outwardly against a mold surface by means of an inner fluid expandable bladder. By this method, the green tire is shaped against the outer mold surface which typically defines the tire's tread pattern and configuration of sidewalls. By application of heat, the tire is cured. Generally, the bladder is expanded by internal pressure provided by a fluid such as hot gas, hot water and/or steam which also participates in the transfer of heat for curing or vulcanization purposes. The tire is then usually allowed to cool somewhat in the mold, sometimes aided by added cold or cooler water to the internal surface of the bladder. Then the mold is opened, the bladder collapsed by removal of its internal fluid pressure and the tire removed from the tire mold. Such tire curing procedure is well known to those having skill in such art.
The use of synthetic rubber compounds in the manufacture of tires makes it necessary to apply suitable coating materials to the rubber surfaces of the fabricated tire carcasses to ensure proper distribution of rubber during the curing operation and the production of finished tires with unblemished surfaces. These coatings are generally liquid in form and are known as lubricants and anti-blemish paints, where the lubricants are applied to the interior surface of a green tire and the anti-blemish paints are applied to the outer surface at the sidewall areas.
The outside green tire paints serve the functions of allowing the rubber to slip as it comes in contact with the metal mold and the paints also serve as a release agent when at the end of the vulcanization cycle, the tire must separate from the mold. Another function of the paint is to provide bleeding of air which becomes trapped between the tire and the mold. Outside green tire paints also aid in the appearance of the finished tire.
Care must be taken that certain areas of the green tire are not coated and that the lubricant employed at the interior of the carcass does not reach any exterior surface of the carcass. Also, applying the coatings manually by either spraying or brushing is time consuming and laborious. Automatic applications, are well known in the art, however, these prior art applications require presorting and separate applicator apparatuses for tire size differences and outer spraying.
U.S. Pat. No. 3,507,247 discloses a coating apparatus including a work-actuated expandable chuck for holding a green tire as the tire is moved through coating and drying zones. The lubricant and paint applying apparatus includes an indexing mechanism for a turret structure which supports identical tire carcass-holding chucks.
The mechanism indexes the carcasses through the spraying and drying steps. Each chuck is manually adaptable to support any size tire carcass. The spray nozzles are manually located relative to the chuck location.
U.S. Pat. No. 5,631,028 discloses a green tire conveyor system for use in a molding machine zone, vulcanizing zone and finishing zone that includes a visual sensor attached to the center of a chuck for locating the center of a green tire via guide marks stamped on the tires. The visual sensor identifies the presence of a green tire and the type of tire. A second distance sensor is attached to a robot for height adjustment of a robot arm corresponding to the type of tire.
U.S. Pat. No. 4,778,060 discloses a tire processing system for sorting tires according to the Department of Transportation's assigned code to each tire manufacturer. The code is optically read by a line-scan camera and sorts green tires using additional information such as: the height of the tire measured from the upper bead, the tire centerline, and other digital optical images transmitted from a camera system located within a painting booth.
Other conventional methods for sorting and spraying the internal and external surfaces of green tires are illustrated in U.S. Pat. Nos. 4,125,639; 5,188,904; and 6,077,469.
While it is known in the art to implement cameras to aid in the locating, conveying and sorting of green tires, it is desirable to provide a vision system that can generate spray positions and fan data based on a two-dimensional image. Further, it is desirable to provide such a system for accurately spraying any size or shaped object with no part specific setup.